Print hammer module apparatus



April 21, 1970 H. A. ANDERsoN 3,507,214

PRINT HAMMER MODULE APPARATUS Original Filed Aug. 14, 1967 2 Sheets-Sheet 1 INVENTOR. .{ILDING A.ANDERSON ATTORNEY A ril 21, 1970 H. A. ANDERSON PRINT HAMMER MODULE APPARATUS 2 Sheets-Sheet Z Onginal Filed Aug. 14, 1967 INVENTOR. HILDING A. ANDERSON AT TORNEY United States Patent U.S. Cl. 101-93 9 Claims ABSTRACT OF THE DISCLOSURE The disclosure relates to a data communication drum printer in which one or more print hammer modules are provided. Each module has a planar frame which mounts four print hammers and an equal number of hammer operator assemblies, the four print hammers being mounted on a common pivot, and the hammer operator assemblies being mounted at spaced apart locations with different angular dispositions about the axis of the common print hammer pivot. Each print hammer has a lever arm terminating at a print head and four shorter actuating lever arms. A hammer operator lever of each hammer operator assembly cooperates with one actuating lever of its respective print hammer to drive the print hammer into printing cooperation with a symbol element of the print drum. A spring biases each print hammer and serves to return the print hammer and its respective operator lever to a normal position out of printing cooperation with the print drum. The normal positions of the print hammers and their operator levers are regulatable while the modules are held in the frame structure. Each individual module is removable from within the printer without disturbing the secured and located arrangement of any other module. The print hammer module can be mounted in stationary frame structure or in a travelling print carriage.

This application is a continuation of copending application Ser. No. 660,408 filed Aug. 14, 1967, now abandoned.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to print hammer module appa' ratus for use in a data communication printer.

BRIEF DESCRIPTION OF THE ART Various arrangements of print hammers and their operators are disclosed for example in US. Patents Nos. 2,940,385, 3,164,085, and 3,417,690.

BRIEF SUMMARY OF THE INVENTION The invention resides in an improved print hammer module, in a bank of such modules, and in frame structure for mounting print hammer modules. The improved module provides for ready regulation of the return position of each print hammer and the respective armature operator lever which operates it by means engageable with the armature operator lever. In addition, there is provision for adjusting the amount of travel of each armature operator lever. The print hammers are all pivotal on a comon axis, and a pluralityof armature operator assemblies are disposed at different spaced apart locations, so that each hammer operator assembly has a different angular disposition about the axis. The frame, which comprises a single generally planar member, mounts a comb which in turn guides and pivotally mounts the print hammers. The comb and the print hammers which it mounts, as well as the hammer operator assemblies are mounted on one side of the planar module ice frame. The module frame mounts an electrical plug board secured to the module frame. The plug board has a plurality of plug connectors with electrical connections to an electromagnet of each armature operator assembly.

Other features of the invention will become readily apparent from the following detailed description and the accompanying drawings, in which:

FIGURE 1 is a partially broken away perspective view of a portion of a drum printer and shows an assembled group of print hammer modules secured on stationary frame structure in accordance with one embodiment of the present invention;

FIGURE 2 is a side elevational view of a print hammer module and a fragmentary portion of a print symbol carrier shown in FIGURE 1;

FIGURE 3 is a fragmentary perspective view of a print hammer module shown in FIGURES 1 and 2, showing in particular a plurality of print hammers mounted on a print hammer pivot in comb structure and fragmentary portions of hammer operator levers;

FIGURE 4 is a sectional view taken along line 4-4 of FIGURE 2;

FIGURE 5 is a fragmentary perspective view of a hammer operator assembly in conjunction with a printed circuit board;

FIGURE 6 is a fragmentary, broken away, view taken along line 6-6 of FIGURE 2;

FIGURE 7 is a view showing fragmentary portions of four hammer operator levers of a module;

FIGURE 8 is a front elevational view of the comb structure shown in FIGURE 3; and

FIGURE 9 is a fragmentary perspective view of a printer having a travellingprint carriage embodying a print hammer module in accordance with the invention.

In general, FIGURE 1 depicts the arrangement of a print drum and a series of novel print hammer modules. The modules are individually clamped in module frame structure secured to the printer frame. Each module has print hammers adapted for movement into printing cooperation wtih the print drum and an equal number of hammer operator assemblies. Ready adjustment of the print hammers is provided while the modules are held clamped in the module frame structure and any module is removable from the module frame structure without disturbing the other modules.

Referring in particular to FIGURES 1 and 2 of the drawings, there is shown a fragmentary portion of a data communication printer generally indicated at 10. A moving print symbol carrier 11 is shown in the form of a rotating print drum, although the purposes of the present invention could also be accomplished if it were a belt-type or any other suitable type of print symbol carrier. The symbol carrier 11 is shown to have rows of identical print symbol or raised type elements 12. A series of print hammer modules 13 are stacked in vertical side-by-side relationship in frame structure generally indicated at 14. The frame structure 14 is shown to include support plates 16 and 17 at each end of a base plate 18, and bars or braces 19, 20, and 21 interconnecting the support plates 16 and 17 by means of threaded fasteners 22. The base plate 18, extending normally with respect to the modules 13, is adjustably secured to the frame 15 of the printer 10 by machine screws 23 (only one of which is shown) which extend through enlarged bores 24 -:in the printer frame 15. The base plate 18 is suitably secured as by threaded fasteners (not shown) to the support plates 16 and 17. Side guides 25 are secured to the frame 15 by threaded fasteners 26. which extend through enlarged bores 27 in the guides 25- and are threadably received in the frame 15. Once the frame structure 14 is aligned with the print symbol carrier 11,

Patented Apr. 21, 1970 i the threaded fasteners 26 can be tightened and thereafter the frame structure 14 can be slid out of position and subsequently slid back into position without further adjustment. As shown in FIGURE 6, an eccentric stop 27 can be adjusted to vary the stop position to which the frame structure 14 and its modules 13 can be moved as a unit with respect to the print symbol carrier 11.

The print hammer modules 13 shown in FIGURE 1 are identical for the sake of interchangeability and economy, and hence only one print hammer module 13 is shown in detail. Each module 13 has a frame 28 which is shown to be of planar form and, in particular, the frame 28 is flat. The frame 28 is preferably blanked out of a single piece of metal as shown, but it can be composed of or formed from other suitable materials as well. Comb structure 29 is mounted to one side of the frame 28 by threaded fasteners 29'. The comb structure 29 is preferably constructed of two combs, one comb 30 having five parallel guide or comb elements 31 and four upstanding lugs 32 and another comb 33 having; five guides or comb elements 34. The comb elements 31 serve both as guides for print hammers 35 and as mounts for a pivot 36 which is common to all the print hammers 35. The pivot 36 mounts the print hammers 35 about a common axis 36'. The comb 33 has five depending lugs 37 which are snugly received by the upstanding lugs 32 and are suitably secured thereto. A compression spring 3-8 disposed between each print hammer 35 and each lug 32 serves to urge the respective print hammer 35 to a normal position out of printing cooperation with the print symbol tour face 40; each print hammer 35 has a bore 35'; and

the print hammers 35 also have short actuating lever arms 41, 42, 43, and 44 which are shorter than the lever arms 39, which are angularly offset from the lever arms 39, and which extend radially outwardly from the axis 36. In particular, the actuating lever arms 41, 42,

43, and 44 form teeth of a circular gear segment. The axis of the gear segment is common with the axis 36'. The lever arms 41, 42, 43, and 44 have involute contoured faces in structural rolling pairing cooperation with respective involute contoured faces at abutment ends 45, 46', 47, and 48 of hammer operator levers 45, 46, 47, and 48. Hammer operator assemblies 49, 50', 51, and 52 and their hammer operator levers 45, 46, 47, and 48 are disposition about the axis 36. The hammer operator 28, so that each hammer operator assembly and its respective hammer operator lever has a different angular disposition about the axis 36'. The hammer operator levers 45 and 46 are bent inwardly toward the hammer operator levers 47 and 48, and the hammer operator levers 47 and 48 are bent inwardly toward the hammer operator levers 45 and 46. The print hammers 35 are equally spaced apart and ends 45', 46", 47', and 48' terminate in adjacent and aligned relationship with respective lever arms 41, 42, 43, and 44. The actuating lever arms 41, 42, 43, and 44 are shown to be at least equal in number to the number of hammer operator assemblies 45, 46, 47, and 48. The hammer operator levers form part of respective hammer operator assemblies generally indicated at 49, 50, 51, and 52.

The hammer operator assemblies 49, 50, 51, and 52 l are arranged in a planar form so that four or more occupy no more lateral width than would one hammer operator assembly. Each hammer operator assembly 49,

ator lever 45, 46, 47, and 48 extends in one direction on one side of the pivot axis of the pivot 58 and toward the axis 36' of the pivot 36 and the respective armature 56 extends in the opposite direction on the opposite side of the pivot axis of the pivot 58. The print coils 55 extend into respective openings 59 in the frame 28. Studs 60 secured in the frame 28 threadably receive stop screws 61 which provide an adjustable stop device for the ends of the levers 45, 46, 47, and 48. The springs 38 normally urge the print hammers 35 counterclockwise as viewed in FIGURE 2 and urge respective levers 45, 46, 47, and 48 clockwise away from the pole faces 54 of respective electromagncts. Thus, the ends of the levers 45, 46, 47, and 48 normally abut their respective stop screws 61 as shown in FIGURE 2. In FIGURE 2 only the first of the four print hammers 35 and springs 38 are seen, the remaining three print hammers 35 and springs 38 being hidden behind them. When the print coil 55 of the selected hammer operator assembly 49 is energized, the armature 56 and its associated hammer operator lever 45 is pivoted counterclockwise, and the involute contoured face at end 45' being in driving engagement with the involute con toured face of the actuating lever arm 41, drives its respective selected first print hammer 35 clockwise into printing cooperation with a print symbol 12 on the print symbol carrier 11.

Inked ribbon R shifts up into the path of the head 40 of the print hammer 35 each time a print hammer 35 is shifted into printing cooperation with the print symbol carrier 11. A record medium R is fed stepwise in linefeed direction between the print symbol 11 and the inked ribbon R by structure (not shown). Neither the inked ribbon R nor the record medium R' are shown in FIG- URE 1 for the sake of clarity. As soon as the print hammers 35 are driven out of contact with the ribbon R by the biasing forces of their respective springs 38 and hammer rebound after the symbols have been printed, the ribbon R is shifted downwardly to the position shown in FIG- URE 2. The symbol or symbols printed in a line on the record medium R can be read when looking down from above the modules due to the fact that the ribbon R is out of the way and modules are so constructed that they-do not obstruct the view. The modules 13 terminate only a short distance above the hammer heads 40 and the comb structure 29 is disposed entirely below the hammer heads 40. By way of example, not limitation, each module is about 0.33 of an inch wide.

Each module 13 has a printed circuit board 62 secured on its one side, as by an adhesive. Although a printed circuit board 62 with only one layer is shown, a multilayered circuit board can be used, if desired. The printed circuit board 62 is shown to have a plastic insulating base 63 and conductors 64 and 64' printed on the base 63. Conductors 64 provide circuit connections for the coils 55. The conductors 64 and 64 are connected to respective diodes 55 and coils 55 of hammer operator assemblies 49, 50, 51, and 52, respectively. The conductors 64 and 64' are connected to individual conductors 65 which extend through respective enlarged bores 66 in flange portion 68 of the frame 28. The conductors 65 are molded into a plug board 69 and their plug terminals 65 extend into sockets 70' molded in a connector board 70. A plug board 69 is suitably secured to each flange portion 68. The connector board 70 extends the full length of the frame 14 and its sockets 70' are in alignment with plug terminals 65' of all the plug boards 69. Prongs 71, which extend into sockets 70, are connected to printer circuitry (not shown).

Any module or modules 13 are individually removable from the frame 13 without disturbing the remaining modules 13 in the frame 14. As best shown in FIGURE 1, each module 13 is individually clamped in the frame 14 by clamp elements 72 and their associated threaded fasteners 73 which when tightened urges its respective module frame 28 against the bar 21. The base plate 18 has parallel equally spaced apart grooves 74 into which the module frames 28 extend. The grooves 74 provide only enough clearance to provide for insertion and removal of the modules 13. The grooves are accurately located and serve to locate the modules 13 and to hold them in their located positions. When it is desired to remove a module 13, its respective threaded fastener 73 is loosened and the clamp element 72 is rotated 90 degrees, out of the path of the module. Threaded fasteners 22 which hold the brace 19 in position are unthreaded and the brace 19 is removed. As clamping surface 75 of each module 13 is parallel with the bottom of the associated groove 74, and as spring-urged ball 76 oifers only slight frictional resistance, the module can be easily pulled out of the frame structure 14. While the module 13 is being pulled out of the frame structure 14, the plug terminals 65 withdraw from sockets 70'. Should it be desired to return the removed module 13 to its former position in the frame structure 14, it is merely slid back into the position it formerly occupied in the frame structure. Each ball 76 exerts only slight pressure on the surface 75 of its respective module 13, and urges the module frame 28 against the base plate 18. The force of each spring 77 is regulatable by means of a set screw 78. The ball 76 and the spring 77 form a resilient clamping structure 79, and there is one such clamping structure 79 for each module frame 28 although only one is shown in FIGURE 2.

During the printing operation, the symbol carrier rotates at a constant rate. If a particular symbol such as a G is to be printed at a particular location along the line, the head 40 of the proper print hammer 35 is driven into printing cooperation with the print symbol G when it is presented in front of that print head 40. Should it happen that the printed line is slightly uneven, it indicates that one or more of the print hammers 35 is driven into printing cooperation with the selected symbol element 12 either too early or too late. With the symbol carrier 11 rotating in the direction indicated by arrow A in FIGURE 2, assuming a symbol is printed too high with respect to other symbols in the line as a result of the print hammer 35 arriving too late at the printing location, an adjustment can be made in the stop screw 61 of its associated hammer operator assembly; namely, the stop screw 61 should be turned to bring the armature 56 closer to the pole face 54' of the electro-magnet 53. The head 40 of that print hammer 35 will then be in a return stop position in closer proximity to the symbol carrier 11. Thereafter, when the coil 55 of that hammer operator assembly is energized, the print hammer 35 will effect recording of the symbol in line with the other symbols in the line, assuming the stop screw 61 has been correctly adjusted. Assuming now that a symbol is printed too low with respect to other symbols in the line as a result of the print hammer 35 arriving too early at the printing location, an adjustment can be made in the stop screw 61 of its associated hammer operator assembly; namely, the stop screw 61 should be turned to bring the armature 56 further away from the pole face 54 of the electromagnet. The head 40 of the print ham mer 35 will then be in a normal stop position further away from symbol carrier 11. Thereafter, when the coil 55 of that hammer operator assembly is energized, the print hammer 35 will eifect recording of the symbol in line with the other symbols in the line, assuming the stop screw 61 has been correctly adjusted. Each core 54 of each elertromagnet 53 is adjustable with respect to the frame 28 by virtue of machine screws threadably received by the frame 28 which extend through enlarged bores 54:. It is preferred that the adjustment of each electromagnet be such that its respective armature abuts the pole face 54 before the head 40 of the print hammer 35 strikes the ribbon R, thus providing a predetermined amount of separation or loss of contact between the hammer operator lever and its related print hammer and free flight of the print hammer. The ends 45, 46', 47', and 48' and the lever arms 41, 42, 43, and 44 are so dimensioned that 6 such separation therebetween is capable of taking place, as indicated in FIGURE 2.

In FIGURE 9 of the drawings, a print hammer module 13, like the one shown in FIGURES 1 through 6 of the drawings, is mounted in a travelling print carriage generally indicated at 80. A guide rod 81 extends through an enlarged bore 82 in the module frame 28 and guidingly receives support plates 83 and 84. The print carriage is guided against rotation about the rod 81 by a guide 85, but can travel lengthwise with respect to the moving print symbol carrier 11. The carriage 80 can be actuated by any suitable means not shown herein but disclosed for example in US. Patent No. 3,280,256.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being best defined by the appended claims rather than by the foregoing description, and all, changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed is:

1. In a data communication printer having a moving print symbol carrier and a plurality of print hammers adapted to be selectively shifted into printing cooperation with record means and desired print symbols on the moving carrier for recording of symbols, the improvement of print hammer module apparatus including at least one print hammer module comprising: frame means, a plurality of print hammers, each print hammer comprising a first lever arm with a print head at its free end and a second actuating lever arm angularly offset from said first lever arm, a plurality of hammer operator assemblies mounted on said frame means, each hammer operator assembly including an armature operator lever, means pivotally mounting all said print hammers on said frame means on a common axis and with said actuating lever arm of each print hammer associated with and adapted to be engaged and operated by an operator lever of a re spective one of said hammer operator assemblies, means individual to and engageable with each armature operator lever for regulating its return position and the return position of the print hammer which it operates, and means securing said hammer operator assemblies at spaced apart locations to said frame means, so that each hammer operator assembly has a different angular disposition about said axis.

2. In a printer as defined in claim 1, wherein said frame means comprises a single generally planar member, each operator lever being disposed on one side of said planar member, a pivot for each operator lever secured to said planar member, comb means disposed on said one side of said planar member for guiding said print hammers, and a pivot for said print hammers carried by said comb means.

3. In a printer as defined in claim 1, wherein each hammer operator assembly includes an electromagnet, an electrical plug board secured to said frame means and including a plurality of plug connectors with electrical connections to each of said electromagnets.

4. In a printer as defined in claim 1, a fixed pivot for each operator lever mounted by said frame means, each armature operator assembly including an electromagnet corresponding to a respective armature operator lever,

means for individually adjusting each electromagnet with respect to said frame means and to its respective armature operator lever to adjust the amount of travel of each armature operator lever, said return position regulating means including a stop screw engageable by a respective armature operator lever, and studs secured to said frame means, each stud threadably receiving one of said stop screws.

5. In a printer as defined in claim 1, each armature operator assembly including an electromagnet corresponding to a respective armature operator lever, and means for individually adjusting each electromagnet with respect to said frame means and its respective armature operator lever to adjust the amount of travel of each armature operator lever.

6. In a printer as defined in claim 1, including a return spring engageable with each print hammer for urging the respective print hammer and the respective armature operator lever toward their return positions, and means individual to and engageable with each armature operator lever for adjusting the amount of travel of the respective armature operator lever.

7. In a data communication printer having a moving print symbol carrier and a plurality of print hammers adapted to be selectively shifted into printing cooperation with record means and with desired print symbols on the moving carrier for recording of symbols: frame structure, a plurality of print hammer modules disposed in side-by-side relationship in said frame structure, each module having a plurality of print hammers, a hammer operator assembly individual to each print hammer, each module having a frame for mounting respective print harnmers and hammer operator assemblies, and means disposed between adjacent module frames for individually adjusting each hammer operator assembly to efiect adjustment of the length of travel of the associated print hammer, said hammer operator assemblies of each module being angularly spaced apart, said frame structure and said modules being sufiiciently open to provide-easy access to enable adjustment of each of said adjusting means while said modules are in said frame structure, and releasable clamping means enabling quick removal of a selected module without disturbing the located and clamped position of the other modules.

- provement of print hammer module apparatus comh 8. In a data communication printer having a moving print symbol carrier and a plurality of print hammers adapted to be selectively shifted into printing cooperation with record means and with desired print symbols on the moving carrier for recording of symbols, the imprising: frame structure, a plurality of print hammer modules disposed in side-by-side relationship in said frame structure, each print hammer module having a plurality of print hammers, means locating each module individually in a predetermined location in said frame structure, and releasable clamping means for each module enabling quick removal of a selected module without disturbing the located and clamped position of the other modules, wherein said frame structure includes bar means extending normally with respect to said modules, said clamping means including spring urged means mounted by said bar for exerting force on each module.

9. In a printer as defined in claim 8, including means for orienting and securely positioning said frame structure and its modules as a unit with respect to said moving print symbol carrier.

References Cited UNITED STATES PATENTS 1,780,674 11/1930 Ewald 101-109 2,874,634 2/1959 Hense 10193 2,940,385 6/1960 House 10193 3,012,499 12/1961 Amada 101111 3,135,195 6/1964 Potter 101---93 3,177,803 4/1965 Antonucci 10193 3,190,957 6/1965 Foley et a1. 17830 3,200,739 8/1965 Antonucci 10193 3,266,418 8/1966 Russo 101--93 3,289,575 12/1966 Wassermay 10l-93 3,314,359 4/1967 Martin 101-93 3,349,696 10/1967 Potter 10193 3,417,690 12/1968 Clark et al 101--93 WILLIAM B. PENN, Primary Examiner US. Cl. X.R. 127-49 zggg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,507,214 Dated April 21, 1970 Inventor(s) Hilding A. Anderson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

column 1,1ine 29, after "respective" insert --hammer--.

Column 3,1ine 49, "disposition about the axis 36' The hammer operator" should read --disposed at equally spaced apart locations to the frame--.

Column 5, line 65, "elertromagnet" should read --electr0magnet-- Column 4, line 70, "frame 13" should read --1rame 14--.

SIGNED AN; SEALED SE? 15am (SEAL) Attest:

Edward M. Fletcher, In.

Amman. 5 Officer mm 1:. sum, :22. L Gomissioner of Patents 

